Electromagnetic switch.



J. 0. SMITH.

ELECTROMAGNETIC SWITCH. APPLIUATIOI FILED 0M. 19, 1911.

1,048,366, Patented Dec.24, 1912.

INVEN TOR.

JOHN C. SMITH, OF LOUISVILLE, KENTUCKY.

ELECTROMAGNETIC SWITCH.

Specification of Letters Patent.

Patented Dec. 24, 1912.

Original application filed July 31, 1911, Serial No. 641,590. Divided and this application filed October 19,

1911. Serial No. 655,512;

To all whom it may concern: V

Be it known that I, JOHN, C. SMITH, a citizen of the United States, and residing'at Louisville, in the county of Jefferson and State of Kentucky, have invented new and useful Improvements 'in Electromagnetic Switches, of which the following'is a specification.

The present invention relates to improve ments in electro-magnetic switches, particularly of the type employed in connection with handling heavy currents inthe control of electric motors, though perhaps useful under other circumstances, and this appli: cation is a division of one filed by me on July 31, 1911, Serial No. 641,590.

hen a circuit, carrying a current of high potential, or one in which there is a large inductance, is broken an arc is formed at the point where the break is made. To disruptthe arc so formed it is customary to form a magnetic field in proximity to the arc, this is done by placing an electromagnet so that the lines of force therefrom will pass at right angles through the gap between the separated conductors.

The object of this invention is to provide an electromagnetic switch in which the magnetic force produced to operate the current breaking means is also utilized to disrupt the arc.

Another object is to produce a switch. of the character described in which the magnetic field .across the gap between theseparated conductors is at its maximum strength when the current is broken, the are being in a measure prevented and at once disrupted.

\Vith the foregoing and other objectsin view, this invention consists of the novel construction, and arrangement of parts to be hereinafter referred to and set forth in the accompanying drawing, which forms .a part of this specification.

Referring to the drawing, in which like reference numerals indicate like parts in the different views; Figure 1, is a plan of the switch. Fig. 2, a section, on line X-X of Fig. 1. Fig. 3, an end elevation, with a portion of the armature and leyer, broken away to show the pole extension of the frame. Fig. 4, a perspectiveof the lever shaft.

Referring to the drawings, 7, indicates a magnet core on which is mounted a winding, 8, the terminals of WlllCh are brought to binding posts, 4 and 5. Frame pieces, 9, of suitable construction are secured, one on means, such as bolts 10. The frames are secured to a base, or panel, 30, of insulating material, such' as slate, by suitable means such as bolts, 29. The forwardend of the frames curve inward, toward each other, forming horns, 22. Secured to the base, or panel, between the horns 22 is a contact post, 1, the top of which does not come quite to the median line of the horns, this post extending through the base and adapted, on the rear thereof, for the attachment of an electrical conductor. A shaft, 11, is mounted in the rear of the frame, near the top thereof, and is electrically insulated therefrom by means of bushings, 12, of insulating material, such as fiber. The shaft 11 extends beyond the frame and is adapted to be each end of the magnet core, by suitable clamped in a post, 3, erected on the base,

said post extending through the base and adapted, on the rear thereof, for the attachment of an electrical conductor, the post being slotted and provided with a screw 13 for clamping said shaft, and preventing the same from turning. Fulcrumed on the shaft is a lever, .2, the forward end of which is adapted to carry a carbon contact, 14, adapted to be brought into contact with the post 1. The rear end of the lever is bifurcated and provided with depending arms, 15, to which an armature, 16, is insulatedly attached by means of washers, 17, and bushings, 18, the arrangement being such that current may enter through the post 3, pass through the shaft 11, lever 2,

contactor 14 and out through the contact post 1, and there will at no time be any current in the frame. A coil spring, 19, centrally located on the shaft, and between the depending arms of the lever, has one end inserted in a slot, 20, in the shaft, and the other hooked over a r,ib of the lever, forward of the shaft. As the' shaft 'is held against movement by the post 3 the tension of the spring serves to hold the carbon contactor 1 1 in'contact with the contact post 1 as long as the magnet is not energized by the passage of a current. Pole extensions, 2 extend inward from the frame on the lower part at the rear end thereof opposite the armature 16 and serve to direct the lines of force to attract the armature.

lVhen the magnet is energized, by the passage-of a current, the armature is attracted by the pole extensions 21 raising the forward end of the lever, against the tension of the spring 19, raising the carbon contactor from the contact post 1. Upon the separation of the contacts 1 1 and 1 an are forms therebetween, and a magnetic field formed between the horns 2:2, and that is directed across the gap, disrupts it. It is to be ob served that the magnetic field between the horns 22 will have attained .maximum strength before the contacts are separated, as the field is formed by the same magnetic flux that attracts the armature and separates the contacts.

A shield, 23, of fireproof material such as asbestos, is placed between the coil 8 and the contact points. Ribs, 24, on the inner sides of the frames being provided to hold the shield. Vertical shields, 25, are secured on each side of the contacts, by means of screws,

26, to extensions, 27, of the post 1. The tension of the spring 19 may be adjusted by loosening the screw 13, in post 3, and turning the shaft 11, a slot, 28, in the end of the shaft providing means for the application of a screw driver for that purpose.

From the foregoing it is thought that the construction, operation and many advantages of the herein described invention will be apparent to those skilled in the art pertaining thereto without further description, and it will be understood that various changes in size, shape, proportion and minor details of construction may be resorted to without departing from the spirit, or sacrificing any of the advantages of the invention.

Having thus described my invention I claim 1. In an electric switch, a-base, a frame thereon, an electromagnet mounted in and magnetically connected with said frame, means for making electrical connections with the magnet, a binding post erected on the base exterior of the frame, a shaft insulatedly mounted in the frame, extending exteriorly thereof and secured in said bind ing post, the frame provided at one end with converging extensions, or horns, a contact post erected on the base and between said horns, a lever fulcrumed on the shaft and in electrical connection therewith, said lever provided at one end with means for holding a contactor adapted to contact with the contact post, an armature insulatedly secured on the other end of the lever, and means for making electrical connections with said con tact and binding posts.

2. An electric switch comprising a base, an electromagnet, frame pieces secured on each end thereof, a lever fulcrumed between said frames, but electrically insulated therefrom, an armature insulatedly secured on one end of the lever, a contactor adjustably secured on the other end of the lever, a post erected on the base and in the path of the contactor, said frames provided with inward extensions adapted to attract said armature, and with converging horns terminating in proximity to the contactor.

3. In an electric switch, a base, a frame thereon, a magnet-core mounted transversely within and magnetically connected with said frame, a magnet-coil on the core, means for making electrical connections with the coil, a binding post mounted on the base exterior of the frame, a shaft insulatedly mounted in the frame, said shaft extending ex'tcriorly of the frame and being secured in said bindin post, a lohgitudinal groove in the shaft, said frame being provided with converging extensions or horn-s, a contact post erected on the base and between said horns, a lever fulerumedon the shaft and in electrical connection therewith, said lever provided at one end with a conductor adapted to be brought into contact with the contact post, an armature insulatedly secured on the other end of the lever, a spring surrounding the shaft with the inner end thereof secured in said slot and the outer end attached to the lever.

JOHN 0. SMITH.

-Witnesses:

WM. J. SAUER, W. B. MUNNELL. 

